Week 4 college football picks: TCU at Texas Tech, UCLA at Arizona, more

We've reached the point in the season where teams begin to show how good they truly are. Over the first three weeks, contenders suffered surprising losses, underdogs slayed giants and perceived middle-of-the-pack squads performed better or worse than expected. There are still plenty of games left to be played in 2015—the first set of College Football Playoff rankings won't be revealed for more than a month—but more ground has already been covered than you probably realize.

This weekend's slate is light on marquee matchups, but there are some intriguing games. Will UCLA or Arizona emerge from their meeting in Tucson as the frontrunner in the Pac-12 South? Can TCU survive a tough test at Texas Tech? SI.com's team of college football writers—Andy Staples, Pete Thamel, Thayer Evans, Zac Ellis, Colin Becht, Lindsay Schnell, Brian Hamilton and Ben Glicksman—offers its predictions for those games and more.​